扬声器力学分布式参数(第一部分:测量篇)(待续)

Distributed Mechanical Parameters of Loudspeakers(Part1:Measurements)(Continued)

扬声器单元的力学振动可以由一组线性的传递函数和几何数据来描述,这些数据是通过测量辐射体(如锥体、半球形膜片、振动盆、活塞、平板等)上的若干个选择点得到的。这些分布式参数是对集总参数(包括T-S、非线性、热学参数)的有益补充,它使得锥体、扬声器单元与扬声器系统设计之间的联系易于理解,并开启了一种新的扬声器诊断方法。重点着眼于激光扫描技术和对数据的后处理。力学振动将会用到一个新的量来概述,即:累积加速度级(AAL),当没有声抵消出现时,它和声压级(SPL)是相当的。这个参数和其他导出的参数是模态分析和全新的分解技术的基础,这一方法使得力学振动和声压输出之间的关系更为明晰。最后,将指出分布式参数在有限元法或边界元分析法中的用法,并给出有益于扬声器设计过程的结论。

The mechanical vibrations of loudspeaker drive units are described by a set of linear transfer functions and geo- metrical data which are measured at selected points on the surface of the radiator （cone, dome, diaphragm, piston, panel）. These distributed parameters supplement the lumped parameters （Thiele -Small, nonlinear, thermal parameters） , simplify the communication between cone, driver, and loudspeaker system design, and open new ways for loudspeaker diagnostics. The laser scanning techniques and the postprocessing of the data are focused on. The mechanical vibrations can be summa- rized as a new quantity, called accumulated acceleration level （AAL） , which is comparable to the sound pressure level （SPL） if no acoustical cancellation occurs. This and other derived parameters are the basis for modal analysis and novel de- composition techniques, which make the relationship between mechanical vibration and sound pressure output more transpar- ent. Finally the usage of the distributed parameters within finite - and boundary - element analyses is addressed and conclu- sions for the loudspeaker design process are drawn.